利比里亚某铁矿矿床地质特征及找矿模型  

Geological Characteristics and Prospecting Model of an Iron Deposit in Liberia

作　　者：郭玉溪[1] 张俊[1] 裴中朝[2,3] 张苗苗 曹宏雷[1] Guo Yuxi;Zhang Jun;Pei Zhongchao;Zhang Miaomiao;Cao Honglei(No.2 Institute of Geological & Mineral Resources Survey of Henan,Zhengzhou 450001,China;Henan Institute of Geological Survey,Zhengzhou 450001,China;Henan Key Laboratory for Metallogenetic Processes of Metal Mineral Resources and Utilization,Zhengzhou 450001,China)

机构地区：[1]河南省地质矿产勘查开发局第二地质矿产调查院,河南郑州450001 [2]河南省地质调查院,河南郑州450001 [3]河南省金属矿产成矿地质过程与资源利用重点实验室,河南郑州450001

出　　处：《金属矿山》2019年第4期129-137,共9页Metal Mine

摘　　要：利比里亚某铁矿位于西非克拉通南部马恩(Man)地盾太古宙成矿区,是典型的沉积变质型铁矿床,规模为一大型铁矿床,由国内企业取得探矿权。太古宙马恩(Man)地盾比里姆绿岩带为区域重要的成矿带,已发现了多处铁矿床与矿点。利比里亚某铁矿为该成矿区的代表性矿床之一,矿体一般呈层状、似层状,整体呈"U"形和"W"形产出。结合1∶25万区域地质调查结果及相关地质工作成果,针对区内第四系覆盖层分布广且厚度大、区域变质程度高、矿体形态较为复杂的特点,开展了高精度磁测和EH4测量。通过地面高精度磁测获得的正磁—负磁—正磁异常分带识别含铁建造区域,根据EH4低阻异常对含铁建造与矿体进行空间定位,结合地质测量、探槽、钻探等手段的综合运用,在该区取得了找矿勘查突破。根据矿床地质特征、地球物理特征、找矿标志等构建了沉积变质型铁矿的找矿模型,并对选定的2处找矿靶区进行验证,取得了较好效果,对于该区后续找矿工作以及沉积变质型铁矿的找矿勘查工作有一定的参考价值。An iron ore deposit in Liberia is located in the Archean metallogenic area of Man Earth Shield in the south of West Africa Craton.It is a typical sedimentary metamorphic iron deposit with a large scale and prospecting rights obtained by Chinese enterprises.The Birimian green rock belt of Archean Man Earth Shield is an important metallogenic belt in the region.There are many iron depoists and mineral occurrences are found in the metallogenic belt.The deposit in Liberia is one of the representative deposits in the metallogenic area,orebodies are generally distributed with layered and stratiform-like,and they are generally exposed with the shape of “U” and “W”.Based on the 1∶250 000 regional geological survey results and some related geological working achievements,in view of the characteristics of widely distributed and thick Quaternary overburden,high degree of regional metamorphism and more complicated orebody shape,high-precision magnetic survey and EH4 survey have been conducted in the area.The iron-bearing formation area can be identified effectively by the zoning of positive- negative-positive magnetic anomalies obtained by high-precision magnetic survey,spatial orientation of iron-bearing formation and orebodies can be conducted based on the low-resistance anomalies acquired by EH4 survey,through the systematic application of geological survey,exploratory trench and drilling,breakthrough in prospecting and exploration has been achieved in the area.According to the deposit geological characteristics,geophysical characteristics and prospecting indicator,the prospecting model of sedimentary metamorphic iron deposit is established.The two delineated prospecting target areas are verified,the prospecting effects is good.The above discussion results can provide reliable reference for the further prospecting work of the area and sedimentary metamorphic iron deposit in other areas.

关 键 词：沉积变质型铁矿 高精度磁测 EH4测量 找矿靶区 矿床成因 找矿模型 

分 类 号：P612[天文地球—矿床学]